Instagram (as far as I can see) has always been a bit quirky. Sticking to low res VGA images for so long stopped me taking it seriously. And even today, simple features like being able to download photos you like seem to be missing. Probably partly for copyright reasons, but mainly to keep the content 100% under Instagram's control. ProGet Universal (a UWP app for all Windows 10, of course) solves the image acquisition issue - and in some style.